4 papers
Isoptic curves of cycloids
Géza Csima
The history of the isoptic curves goes back to the 19th century, but nowadays the topic is experiencing a renaissance, providing numerous new results and new applications. First, w…
Isoptic surfaces of segments in and geometries
Géza Csima
In this work, we examine the isoptic surface of line segments in the and geometries, which are from the 8 Thurston geometries. Based on the procedure fi…
Translation-like isoptic surfaces and angle sums of translation triangles in $\NIL$ geometry
Géza Csima, Jenő Szirmai
After having investigated the geodesic and translation triangles and their angle sums in $\SOL$ and $\SLR$ geometries we consider the analogous problem in $\NIL$ space that is one…
The sum of the interior angles in geodesic and translation triangles of Sl2(R) geometry
Géza Csima, Jenő Szirmai
We study the interior angle sums of translation and geodesic triangles in the universal cover of Sl2(R) geometry. We prove that the angle sum is larger then pi for translation tria…